Effects of underwater explosion depth on shock wave overpressure and energy

In this paper, the effects of the water depth on the overpressure (pressure difference between positive shock pressure and hydrostatic pressure) peak and energy of underwater explosion shock waves were analyzed. Two quantitative calculation models were established that accounted for the effect of the water depth, which have theoretical and practical engineering value. A simulated deepwater explosion tank test was first conducted to obtain experimental data of the overpressure peaks and energies of the explosion shock waves generated by 10 and 30 g trinitrotoluene (TNT) explosives in a simulated environment at water depths of 400, 500, and 600 m. A one-dimensional wedge-shaped Euler grid numerical model was established to simulate the underwater explosion using the Autodyn software. The simulation model was validated by the experimental data to prove its accuracy and rationality. Then, numerical simulations were carried out at 13 operating conditions with 30 g of TNT in a full water depth range of 0-5000 m. Based on the simulation data analysis, the calculation models of the overpressure peak and energy flow density of the underwater explosion shock wave were obtained, which contain water depth correction functions. The results show that both the overpressure peak and the shock wave energy decreased with increase in the water depth, but the reduction percentage of the overpressure peak with the water depth was very small. The overpressure peak and energy flow density of the shock wave agreed with the explosion similarity law at all fixed water depths. The proposed calculation models have practical engineering value and generalization ability.